1. Field of the Invention
The present invention relates to the field of computer networking, specifically to the field of monitoring, viewing and altering information regarding devices coupled with a computer network.
2. Description of the Related Art
The present invention relates to methods and apparatus for monitoring, viewing and altering information regarding devices coupled with or within a computer network. In particular, the present invention is directed to a monitoring, viewing and altering information regarding routers which are commonly utilized in computer networks. It is important in management of data networks to provide the network manager (e.g., a person assigned the responsibility for overseeing the operations and overall health of the network) with information on various devices in the network.
Routers
Routers are generally characterized in that such devices provide for interconnecting portions of data networks and provide for message packet routing and forwarding between such multiple networks. Routers generally operate at the network layer of the ISO protocol.
Routers are available from a number of vendors. For example, Cisco Systems, Inc. provides a family of routers including, by way of example, the Cisco 4000 router. Typically, routers (such as the Cisco 4000 router) include both hardware and software components. In providing information on a router to a network management system, it is important to provide information on both the hardware and software components. For example, it might be desirable to provide the network management system with information on the router, on the various network protocols available on the router, and on the various interfaces available on the router.
SNMP
One relatively standardized network management tool is the Simple Network Management Protocol (SNMP). This protocol provides for three elements: (1) the manager, (2) the agent, and (3) the management information base (MIB). SNMP is described in greater detail in, for example, Naugle, Local Area Networking, McGraw-Hill, Inc., 1991, pp. 221-225. SNMP is also described in Schnaidt, Keep it Simple: SNMP lets you manage a heterogeneous network today, LAN Magazine, July 1990, pg 82.
Generally, SNMP may be characterized as a request-response protocol which contains a manager and an agent. The agent is typically located on a network device (e.g., a router). The agent is generally passive and performs operations responsive to polling from a manager. The one exception to the rule of the agent being passive and simply responding to requests from the manager is that an agent will generally communicate to the manager when certain "trap" conditions are detected. In any event, the agent generally acts gather information about its own device's internal workings and the network and stores the information in the MIB. Using a connectionless protocol the manager requests and obtains information from the MIBs.
Sometimes, the device executing the management applications that are used to poll the agents on the network is referred to as the "management station" and the devices which contain the agents are referred to as "managed elements".
There exists certain standards for the MIB as well as "extensions" to the MIB which allows each network device vendor to provide its specific information for its own devices.
Although SNMP provides for the ability to poll a device implementing an SNMP agent, SNMP does not provide standards for how information received from the agent is to be displayed or presented to the network manager.
Many commercially available routers have implemented SNMP agents.
Telnet
Although significant information is available from network devices, such as routers, using SNMP, certain information may not be available using the standard SNMP interface. For example, diagnostic information on certain routing tables may not be available using SNMP. However, many network devices, including many routers, provide for remote diagnostic access using the standard Telnet protocol. The Telnet protocol provides a terminal emulation capability allowing a network manager to issue commands (such as commands requesting diagnostic information) from other devices in the network
Importantly, the Telnet protocol provides information to network management devices in an ASCII character format. Thus, although much information may be obtained using the Telnet protocol, reading and understanding the information presented typically requires significant training and effort. Further, it typically requires significant training and effort to learn the various commands which may be used to obtain information from a device using the Telnet protocol.
Physical representation of network devices
One well-known example of tool which provides information to a network manager is the Expanded View.TM. network management module available from SynOptics Communications, Inc., the assignee of the present invention. Generally, the Expanded View network management module provides for a graphical display of a physical view of devices in a network. For example, a concentrator hub in a data network may be displayed. The concentrator hub physically may include, for example, module cards which are inserted into the concentrator hub. The concentrator hub and the various module cards may include status indicators such as LEDs which provide status information on the cards and the hub. In many circumstances, it is useful to be able to obtain the status information which is provided by the status indicators as well as to be able to physically view the hub to see what modules are currently in the hub and to see which ports on those modules may have existing physical connections. However, the concentrator hub is often located physically remote from the network manager. Therefore, the Expanded View network management module provides a physical representation of a selected concentrator in the form of a graphical image complete with representation of each of the installed modules and the various status indicators (i.e., LEDs) provided on the module. This physical representation may be provided on network management station which may located in a location physically convenient for access by the network manager. The Expanded View network management module is one module in the Optivity.TM. network management system, also available from SynOptics Communications, Inc.
U.S. Pat. No. 5,226,120 (the '120 patent) titled "Apparatus and Method for Managing the Status of a Local Area Network", which patent is assigned to the assignee of the present invention and is incorporated herein by reference, describes certain aspects of displaying physical representations of concentrator hubs in greater detail. For example, FIG. 7 of the '120 patent (which is discussed, for example, at column 8, line 41 et seq.) illustrates an exemplary pop-up detailed window which is displayed on a network management station when the exemplary concentrator is selected. As is described in the patent, the concentrator is displayed as a physical representation of the actual concentrator and includes, in the example shown in FIG. 7 of the '120 patent, thirteen plug in modules represented as image sections 60a-60m in the figure. At column 9, line 13 et seq. it is discussed that status information is shown in the form of the LED lights.
Importantly, the Expanded View network management module and the concentrators it is used to manage are generally characterized by two factors:
(1) the Expanded View network management module and the concentrators are both manufactured by, or in cooperation with, a single manufacturer (i.e., SynOptics). This allows SynOptics to control and design how information is exchanged between the Expanded View module and the concentrators; and PA1 (2) a representation of a physical view of a concentrator hub conveys significant information to the network manager because of, for example, the ability to display representations of status information in the form of LEDs. However, the displayed physical representation does not readily lend itself to representation of certain devices which may be attached to networks, such as routers, which have both hardware and software components to be monitored and which do not necessarily provide physical indications of status, such as LEDs.